Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 651: Which of the following gases is the most dangerous pollutant? Options:
  A) Hydrogen sulphide
  B) Carbon (lV) oxide
  C) Sulphur (lV) oxide
  D) Carbon (ll) oxide
  Show Answer
  The correct answer is D .
• Question 652: Carbohydrates are large molecules with the molecular formula C _x (H₂O)_y. In which of the following pairs is x not equal to y? Options:
  A) glucose and starch
  B) maltose and starch
  C) sucrose and fructose
  D) maltose and starch
  Show Answer
  The correct answer is A .
• Question 653: Ethanol can easily be produced by Options:
  A) fermentation of starch
  B) distillation of starch solution
  C) catalytic oxidation of methane
  D) destructive distillation of wood
  Show Answer
  The correct answer is A .
• Question 654:

  

  The function of the copper (ll)tetraoxosulphate (IV) in dilute H₂SO₄ in the figure above is to

  Options:
  A) dry the gas
  B) absorb phosphine impurity
  C) absorb ethene impurity
  D) from an acetylide with ethyne
  Show Answer
  The correct answer is B .
• Question 655: Ethanol reacts with excess acidified K₂Cr₂O to produce Options:
  A) ethanedioic acid
  B) ethanal
  C) ethylethanoate
  D) ethanoic acid
  Show Answer
  The correct answer is D .
• Question 656:

  What volume of oxygen will remain after reacting 8cm of hydrogen gas with 20cm of oxygen gas

  Options:
  A) 10cm${}^3$
  B) 12cm${}^3$
  C) 14cm${}^3$
  D) 16cm${}^3$
  Show Answer
  The correct answer is D .
• Question 657: An organic compound reacted with bromine water to give a colourless solution. The compound is probably an Options:
  A) alkene
  B) alkanal
  C) alkyne
  D) alkanone
  Show Answer
  The correct answer is C .
• Question 658: In the Haber process for the manufacture of ammonia, the catalyst commonly used is finely divided ? Options:
  A) vanadium
  B) platinum
  C) iron
  D) copper
  Show Answer
  The correct answer is C .
• Question 659:

  Na${}_2$CO${}_3$ + 2HCl $\to$ 2NaCl + H${}_2$O + CO${}_2$

  The indicator most suitable for this reaction should have a pH equal to

  Options:
  A) 5
  B) 7
  C) 3
  D) 9
  Show Answer
  The correct answer is C .
• Question 660: Trioxonitrate (V) acid is not used for preparing hydrogen gas from metals because it Options:
  A) is strongly oxidizing
  B) is volatile
  C) renders the metal passive
  D) forms a layer of oxide on the metal
  Show Answer
  The correct answer is A .